CVE-2020-2252 is a medium-severity (CVSS 4.8) CWE-295 vulnerability in org.jenkins-ci.plugins:mailer. A fix is available for org.jenkins-ci.plugins:mailer — see the affected versions and patch details below.
Improper Validation of Certificate with Host Mismatch in Jenkins Mailer Plugin
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.jenkins-ci.plugins:mailer☕org.jenkins-ci.plugins:mailer☕org.jenkins-ci.plugins:mailerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Jenkins Mailer Plugin prior to 1.32.1, 1.31.1, and 1.29.1 does not perform hostname validation when connecting to the configured SMTP server. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections.
Mailer Plugin 1.32.1, 1.31.1, and 1.29.1 validates the SMTP hostname when connecting via TLS by default. In Mailer Plugin 1.32 and earlier, administrators can set the Java system property mail.smtp.ssl.checkserveridentity to true on startup to enable this protection.
In case of problems, this protection can be disabled again by setting the Java system property mail.smtp.ssl.checkserveridentity to false on startup.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.plugins:mailer | ≥ 1.32&&< 1.32.1 | 1.32.1org.jenkins-ci.plugins:mailer:1.32.1 |
| ☕Maven | org.jenkins-ci.plugins:mailer | ≥ 1.30&&< 1.31.1 | 1.31.1org.jenkins-ci.plugins:mailer:1.31.1 |
| ☕Maven | org.jenkins-ci.plugins:mailer | all versions | 1.29.1org.jenkins-ci.plugins:mailer:1.29.1 |
Affected Products
mailerjenkinsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:mailer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jenkins-ci.plugins:mailer to 1.32.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-2252 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 3.11 | jenkins-2-plugins-0:3.11.1603460090-1.el7 | RHSA-2020:5102 |
| Red Hat OpenShift Container Platform 4.6 | jenkins-2-plugins-0:4.6.1601368321-1.el8 | RHSA-2020:4297 |
Frequently Asked Questions
Is CVE-2020-2252 in your dependencies?
Find it across Maven, including transitive dependencies.